FORT STEWART, Ga. (AP) — A civilian medical examiner testified Wednesday he's confident a pregnant Army soldier was strangled to death as she struggled violently against handcuffs — an opinion that contradicts the military's official autopsy findings that no cause of death could be determined.

Dueling expert opinions could prove pivotal in the court-martial of Pvt. Isaac Aguigui, who is charged with murdering his wife, Sgt. Deirdre Aguigui, and with causing the death of their unborn child. The 22-year-old defendant faces an automatic life sentence if convicted of murder by a military judge, who will decide the case instead of a jury of fellow soldiers.

Isaac Aguigui of Cashmere, Wash., told investigators he found his wife dead on the couch inside their apartment on Fort Stewart the night of July 17, 2011. She had no fatal injuries, but numerous bruises were found on her wrists, arms, back and head. The wrist injuries appeared to match a pair of handcuffs on the couple's bed, and the husband told investigators he had cuffed his wife during consensual sex earlier that evening.

Military medical examiners were stumped. Their 2011 autopsy found no proof of an attack, illness, allergy, drug overdose or anything that could explain why 24-year-old Deirdre Aguigui died. Lt. Cmdr. Lisa Rivera, who performed the autopsy, told the judge she couldn't even determine if the woman had been killed or died from natural causes.

Dr. James Downs, a Georgia state medical examiner, testified Wednesday that a lack of any other cause indicates Deirdre Aguigui died because something stopped her from being able to breathe. He said more than 20 fresh bruises and scrapes on her body point to some type of violence, and the deep wounds on her wrists appear too excessive to have come from being consensually bound during sex. He concluded she was cuffed and held in a chokehold that would have left virtually no telltale injuries on her neck.

"I am confident to a reasonable degree of medical certainty," said Downs, who estimated he's performed 4,500 autopsies. "We know for a fact she is violently struggling against those handcuffs."

Defense lawyers insisted Downs' findings were far from conclusive.

"It seems to me you're speculating," said Capt. William Cook, one of Aguigui's Army lawyers.

Prosecutors rested their case Wednesday during the third day of testimony. They introduced records showing Isaac Aguigui received $500,000 in life insurance and benefit payments from the Army after his wife's death. Army investigator Justin Kapinus said bank records showed Aguigui spent $6,000 or more at strip clubs in the months following his wife's death and bought $30,000 worth of guns and ammunition in his home state of Washington.

Army prosecutors said Aguigui faced getting kicked out of the Army for unspecified disciplinary infractions at the time of his wife's death. They say he used the insurance money to buy guns because he planned to start a private security business.

Civilian prosecutors in a different case have painted a more sinister portrait. They say Aguigui stockpiled weapons after starting an anti-government militia group with other disgruntled soldiers. Nearly five months after his wife died, Aguigui and three other soldiers were charged in the December 2011 slayings of a former member of their unit and his girlfriend. Civilian prosecutors say Aguigui ordered their deaths to protect the group. He pleaded guilty to murder charges last July and is already serving life without parole in a Georgia prison.

Deirdre Aguigui's father, Alma Wetzker, testified Wednesday his daughter was "raging and scared" when she called him two days before her death. She told him her husband had left Fort Stewart on a weekend trip to South Carolina, leaving her without transportation or money for food. Wetzker said his son-in-law was struggling with a drug problem and didn't seem to be improving.

"I asked her if she was planning to leave Isaac until he got his act together," Wetzker said. "She said she would talk to him when he returned Sunday."

By the end of that weekend, his daughter was dead.

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